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Neal and Carrawan 2004 NC State Univ
What Do Weeds Do?What Do Weeds Do?Compete with crops for resources
Interfere with crop quality and quantity
Reduce aesthetics of landscapeAffect function of turfgrassDisplace native flora
Neal and Carrawan 2004 NC State Univ
What Do Weeds Do?What Do Weeds Do?Cause allergiesHarm peopleHarbor insects and plant pathogens
Ragweed pollen causes hay fever
Neal and Carrawan 2004 NC State Univ
Weeds -- How Did They Get There?Weeds -- How Did They Get There?
Every shovel full of soil contains thousands of weed seeds -- waiting for an opportunity
Often we just provide the weeds with the opportunity and environment to flourish
Neal and Carrawan 2004 NC State Univ
Weed Seed Are Spread By:Weed Seed Are Spread By:
WindPeopleRain runoffBirds and other animals
Garden cultivation
Mowing Topsoil or
compost addition
Purchased plants
Neal and Carrawan 2004 NC State Univ
Invaders - weed dispersalInvaders - weed dispersalWind Surface waterBirds & animalsActivities of man
–site prep, cultivation, planting
Neal and Carrawan 2004 NC State Univ
How we introduce and move weeds
How we introduce and move weeds
–top soil–organic amendments–equipment–plants
Neal and Carrawan 2004 NC State Univ
Crabgrass
Kudzu
Multiflora rose
And, sometimes we intentionally introduce weeds
And, sometimes we intentionally introduce weeds
Neal and Carrawan 2004 NC State Univ
Bamboo
Water hyacinth
Japanese knotweed
More Plants (weeds) Intentionally Introduced More Plants (weeds) Intentionally Introduced
Neal and Carrawan 2004 NC State Univ
The First Step in Weed Management is Identification!
Weed Identification – Its More Than Knowing a Name!
The First Step in Weed Management is Identification!
Weed Identification – Its More Than Knowing a Name!
Neal and Carrawan 2004 NC State Univ
Why is it Important to Identify Weeds?Why is it Important to Identify Weeds?So you know
–when it germinates,–how it spreads,
And, so you can determine the most appropriate control measure(s) -- herbicides, cultivation, mulches, etc.
Neal and Carrawan 2004 NC State Univ
How do you correctly identify a weed?How do you correctly identify a weed? Compare to a photo
–Remember weeds can appear different due to site conditions
–Easiest to do when plant is flowering
Keys to Identification Send a sample to the local
Cooperative Extension office
Neal and Carrawan 2004 NC State Univ
Identification ResourcesIdentification ResourcesFor Piedmont and Coastal Plains
–Identifying Seedling and Mature Weeds in the Southeastern US
–Weeds of Southern TurfgrassMountains
–Weeds of the Northeast–Weeds of Southern Turfgrass
Neal and Carrawan 2004 NC State Univ
How to order:How to order:
Identifying Seedling and Mature Weeds in the Southeastern US (AG-208) – Publications Office, Box 7603 NCSU, Raleigh, NC 27695-7603 $10.00
Neal and Carrawan 2004 NC State Univ
How to order:How to order: Weeds of Southern
Turfgrass– Publication Distributions
Center IFAS Building 664 P. O. Box 110011 University of Florida Gainesville, FL 32611 (352-392-1764) $8.00 +
$3.00 shipping
Neal and Carrawan 2004 NC State Univ
How to order:How to order:
Weeds of the Northeast –Cornell University Press P. O. Box 6525 Ithaca, NY 14851-6525 607-277-2211 $29.95 plus $5 shipping
Neal and Carrawan 2004 NC State Univ
Some Web-Based Weed ID ResourcesSome Web-Based Weed ID Resources
www.ces.ncsu.edu/depts/hort/weeds www.ppws.vt.edu/weedindex.htm www.rce.rutgers.edu/weeds/ axp.ipm.ucdavis.edu/PMG/
weeds_common.html www.psu.missouri.edu/fishel/ www.ppws.vt.edu/newss/weedid.htm www.griffin.peachnet.edu/cssci/TURF/
turf.htm
Neal and Carrawan 2004 NC State Univ
How to send a sample for IDHow to send a sample for ID
Fresh samples: moisten sample; wrap in DRY paper towel; put in a zip-lock bag and mail on Monday or Tuesday to the appropriate specialist
Neal and Carrawan 2004 NC State Univ
How to send a sample for IDHow to send a sample for ID
If you cannot send it right away (or if you get the sample on Thursday or Friday: Lay flat on between newspaper; press.
Mail the dried, pressed sample to the appropriate specialist
Neal and Carrawan 2004 NC State Univ
Use the Sample Submission FormUse the Sample Submission Form
http://intra.ces.ncsu.edu/depts/cs/weedforms/2weedide.pdf or
http://www.cropsci.ncsu.edu/turffiles/weedid/weedid.htm
http://www.cropsci.ncsu.edu/aquaticweeds/weed_id/aquatic.htm
Neal and Carrawan 2004 NC State Univ
Weed ClassificationWeed Classification
Ways weeds are classified–Lifecycle–Seed leaves–Growth habit–Susceptibility to herbicides
Neal and Carrawan 2004 NC State Univ
Life cycle of an annual weed
SeedSeedling
Plant flowers
Plant setsseed
Plant dies
Neal and Carrawan 2004 NC State Univ
Life cycle of a winter annual weed
SeedSeedling
Plant flowers
Plant setsseed
Plant dies
FallSummer
Neal and Carrawan 2004 NC State Univ
Life cycle of a summer annual weed
SeedSeedling
Plant flowers
Plant setsseed
Plant dies
SpringFall
Neal and Carrawan 2004 NC State Univ
Common Summer Annual WeedsCommon Summer Annual Weeds
J. N
eal
J. N
eal
J. D
err
J. N
eal
Neal and Carrawan 2004 NC State Univ
Life cycle of a biennial weed
SeedSeedling
Plant flowers
Plant setsseed
Plant dies
Over-winters as
a rosette
First Season
Second Season
Neal and Carrawan 2004 NC State Univ
Common BiennialsCommon Biennials
Bull Thistle Queens Ann’s LaceMullein
J. D
iTom
aso
R. U
va
J. N
eal
Neal and Carrawan 2004 NC State Univ
Life cycle of a perennial weed
Seed Seedling
PlantFlowers
PlantOver-winters
Plant setsSeed
Roots/ rhizomesspread
New plant
Neal and Carrawan 2004 NC State Univ
Some common perennial weedsSome common perennial weeds
J. N
eal
J. N
eal
J. N
eal
R. U
va
R. U
va
Neal and Carrawan 2004 NC State Univ
Perennial Weeds Reproduce By:Perennial Weeds Reproduce By:
Rhizomes
Tubers
Stolons
Bulbs
Seeds
Neal and Carrawan 2004 NC State Univ
Types of Perennial Weeds Types of Perennial Weeds Simple perennials Creeping perennials
–Rhizomes–Stolons –Creeping roots that produce shoots
Tuberous perennialsBulbous perennials
Neal and Carrawan 2004 NC State Univ
Simple PerennialsSimple Perennials
Spread by seedTap root or hardy fibrous root system
Examples: dandelion, plantain, dogfennel, pokeweed
Tap root
Neal and Carrawan 2004 NC State Univ
Creeping PerennialsCreeping Perennials
Reproduce and spread by – Underground stems (rhizomes)– Above-ground stems (stolons)– Creeping fleshy roots that
produce new shoots Many also reproduce by
seeds or other means.
Stolon
Rhizome
Neal and Carrawan 2004 NC State Univ
Tuberous PerennialsTuberous Perennials
Tubers are swollen, modified stems that are often resilient to controls, spread by cultivation, and may persist in the soil for years.
Tubers form on rhizomes
Tubers
J . N
e al
Neal and Carrawan 2004 NC State Univ
Bulbous PerennialsBulbous Perennials
Persist through the dormant season as a bulb
Wild garlic and wild onion produce bulblets, aerial bulblets, and seeds
R. U
v a
Neal and Carrawan 2004 NC State Univ
Weeds Are Also Classified By:Weeds Are Also Classified By:Cotyledons (Seed leaves)
Monocot (one seed leaf)
Dicot (two seed leaves)
Neal and Carrawan 2004 NC State Univ
MonocotsMonocots
One seed leaf when plant emerges
Long narrow leaves
Parallel veins
Neal and Carrawan 2004 NC State Univ
Monocots -- ExamplesMonocots -- Examples
GrassesOnionsGarlic
SedgesRushesLiliesDayflower
Neal and Carrawan 2004 NC State Univ
GrassesGrassesRounded or flattened stems and nodes
Have fibrous root systemsSome have fibrous roots, rhizomes or stolons for reproduction
Growing point is below surface
Neal and Carrawan 2004 NC State Univ
Grasses are identified by:
seedhead
blade
ligule
auricles
collar
bud leaf
rhizome
stolon
midrib
sheath
crown
Neal and Carrawan 2004 NC State Univ
Vernation or Leaf BudVernation or Leaf Bud
Rolled in the bud Folded in the bud
Neal and Carrawan 2004 NC State Univ
Absent Membranous Hairy
The
Sco
tts
Co.
The
Sco
tts
Co.
The
Sco
tts
Co.
LigulesLigules
Neal and Carrawan 2004 NC State Univ
Absent Present Clasping
The
Sco
tts
Co.
The
Sco
tts
Co.
The
Sco
tts
Co.
AuricleAuricle
Neal and Carrawan 2004 NC State Univ
Branched spikePanicle Spike
SeedheadsSeedheads
The
Sco
tts C
o.
The
Sco
tts C
o.
The
Sco
tts C
o.
Neal and Carrawan 2004 NC State Univ
Grass-Like WeedsGrass-Like Weeds Sedges: Sedges have triangular
“stems”. Grasses have flat or rounded “stems”.– Annual and perennial species– Most common and difficult to control
are yellow and purple nutsedge Wild Garlic and wild onion: hollow
leaves have a pungent onion-like or garlic-like aroma– Wild garlic is the most common
Neal and Carrawan 2004 NC State Univ
Yellow and Purple Nutsedges (Cyperus spp.)
Yellow and Purple Nutsedges (Cyperus spp.)
Grass-like, but “Sedges have edges” – triangular “stems”
Leaves emerge 3-ranked
Spread by rhizomes and over-winter as tubers
Tubers often introduced in top soil
A. S
enes
acJ.
Nea
l
Neal and Carrawan 2004 NC State Univ
Yellow Nutsedge (Cyperus esculentus)
Yellow Nutsedge (Cyperus esculentus) Perennial with
rhizomes and tubers Emerge in late
spring; die in the fall “Daughter” plants
and tubers formed at tips of rhizomes
One plant can form as many as 6000 tubers
R. U
vaJ.
Nea
l
Neal and Carrawan 2004 NC State Univ
PurpleNutsedge (Cyperus rotundus)
PurpleNutsedge (Cyperus rotundus) Rhizomatous and
tuberous perennial Emerge in mid-
spring; die in the fall
Forms tubers within 6 weeks of emergence
Very hard to control The “world’s worst
weed”
J. N
eal
Forms tubers in “chains”
J. N
eal
Neal and Carrawan 2004 NC State Univ
Yellow vs. Purple – Leaf tipsYellow vs. Purple – Leaf tips
Yellow nutsedge leaf tips taper to a long, narrow point
Purple nutsedge leaf tips are pointed but not tapered
Yellow PurpleJ.
Nea
l
Neal and Carrawan 2004 NC State Univ
Yellow vs. Purple -- FlowersYellow vs. Purple -- Flowers
Yellow fading to tan
Yellow Nutsedge
J. D
err
Purple or reddish brown turning black
Purple Nutsedge
J. N
eal
Neal and Carrawan 2004 NC State Univ
Wild Garlic (Allium vineale)
J. N
eal
R. U
va
Aerial bulblets
Bulbous perennial
Strong scent Reproduces
by bulblets, rarely by seed
Emerges in the winter and dies back in late spring or early summer
Neal and Carrawan 2004 NC State Univ
Dicots or Broadleaf weedsDicots or Broadleaf weeds
Two seed leaves (cotyledons)
Leaves have netted veinsLargest group of weedsOften with bright showy flowers
Exposed growing points
Neal and Carrawan 2004 NC State Univ
How to ID DicotsHow to ID Dicots
FlowersUnique CharacteristicsGrowth HabitLeaf Orientation, Shape, Etc.
Neal and Carrawan 2004 NC State Univ
Unique CharacteristicsUnique Characteristics
Look for:–Thorns or spines–Square or winged stems–Compound leaves–Whorled leaves–Milky sap
R. U
va
Neal and Carrawan 2004 NC State Univ
Leaf OrientationLeaf Orientation
Opposite
Alternate
Whorled
Rosette
Neal and Carrawan 2004 NC State Univ
Simple Verses Compound LeavesSimple Verses Compound Leaves
R. U
va
Simple
Pinnate Palmate
Compound
J. D
err
Neal and Carrawan 2004 NC State Univ
Other Ways to Identify Cont.Other Ways to Identify Cont.Leaf shapeLeaf margin
–Toothed,entire,lobed, or deeply cut
Petiole lengthHair on leaves or other parts
Neal and Carrawan 2004 NC State Univ
Leaf MarginsLeaf MarginsR
. Uva
J. D
itom
aso
Entire
Deeply lobed
Shallow lobes or toothed
Neal and Carrawan 2004 NC State Univ
Hairs – present or absent, & where?Hairs – present or absent, & where?
J. D
iTom
aso
Mouseear chickweed -- Hairs on stem & leaves
Common chickweed -- Hairs absent
J. N
eal
Neal and Carrawan 2004 NC State Univ
Tell Me What You See?Tell Me What You See?
RosetteBroad, nearly entire leaves
5 veinsFlowers on spikes
Broadleaf plantain